The ZTZ series inclined screw conveyor, also called sedimator, applies for processing heavy rejects discharged from H.C. cleaners and all screens, such as sand, nails, glass, stone and metal particles. It consists of the guiding device, drive device and other components. This sand separator can efficiently separate rejects from pulp with the use of their different specific gravity, so as to remove rejects and recover accepts. It greatly reduces pulp loss and saves consumption.